Telephone.



PATENTED JAN. 9, 1906.

C. G BURKE. TELEPHONE APPLICATION FILED SEPT/16. 1901.

v UNITED STATES PATENT OFFICE.

CHARLES Gr. BURKE, OF BROOKLYN, NEW YORK, ASSIGNOR OF ONE-HALF TO JOHN Q. A. WHITTEMORE, OF BOSTON, MASSACHUSETTS.

TELEPHONE.

Specification of Letters Patent.

Patented Jan. 9, 1906.

Application filed September 16, 1901. Serial No. 75,434.

To aZZ whom it may concern:

Be it known that I, CHARLES Q. BURKE, a citizen of the United States, residing in the borough of Brooklyn, in the city of New York, county of Kings, and State of New York, have invented certain new and useful Improvements in Telephones, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.

The invention which forms the subject of my present application is an improved telephone-receiver consisting of a core of magnetic metal, a vibrating diaphragm, and two coils of insulated wireone of few turns of coarse wire, the other of many turns of fine wire. The coils may be connected together and with the line wire or circuit in series, or they may be connected in such a way as to form theprimary and secondary coil of an induction-coil.

I have found that when an ordinary telephone-receiver is provided with two coils of the kind described and connected in series with the. line a very much better result with respect to the loudness and distinctness of the reproduced speech is obtained. I have also found that such an instrument is useful in many forms of systems and telephonic connections. It is, moreover, particularly adapted to a system devised by me in which the receiving means is composed of two magnetic telephones. Under such conditions the receiver or magnetic telephone gives very efficient results.

In the accompanying drawings I have illustrated my improved receiver and the manner of its connection or use.

Figure 1 is a longitudinal section of the instrument, and Fig. 2 is a diagram illustrating the same connected with the circuit.

The general shape and construction of the receiver is or may be similar to that of the ordinary magneto telephone, comprising a handpiece A, a core B, and a diaphragm O.

' In lieu of the usual coil I employ two coils D and E in inductive relation to each other and in general bearing to each otherthe same relations as those employed in the ordinary induction-coils employed on telephone-circuits. One of these coils, as D, is of coarse wire of comparatively few turns, and preferably wound upon the core or inside of the other coil E, which is of fine wire of many turns. The terminals of these coils may be permanently connected in the manner or order in which they are designed to be used; but for convenience they are, by preference, carried to four binding-posts F, which may be connected to the line in any desired manner. The order of connections to be observed is illustrated in Fig. 2, in which one line-wire G is shown as connected to one terminal of the finewire coil E. The other terminal 'of this coil is connected with one terminal of the coarse-wire coil D, while the other terminal of the latter is connected with the other line-wire H. This instrument has an additional feature of usefulness, in that it is capable of serving both as a receiver and as an induction-coil for transmitting. For this purpose the two terminals of the coarse-wire coil D may be connected in a local circuit containing a transmitter K and a battery L. As illustrated in Fig. 2, the coil is connected in series with the transmitter K and the battery L, and when so connected it constitutes the primary coil of an inductorium. The high-potential current passing through the fine-wire coil, which acts as a secondary coil of the inductorium, cooperates with the transformed current of high amperage produced in the primary coil to greatly eflect the diaphra m of the telephone-receiver. It

'will also be ound that if a second telephone- .receiver of any kind, as M, be inserted in the circuit between the coarse and fine wire coils and used together with the firstthat is to say, by holding both instruments to the cars at the same timea much louder and clearer reproduction of speech will be observed than by the use of either instrument separately or by the use of two in either the line or local circuit. When the receiver is thus inserted, the main-line circuit is completed through the fine-wire coil or secondary coil to the receiver M, and then through the double branch of the low resistance, or the two parts formed in the local circuit by the connections, back to the main line. By this form of a receiver I have reduced the number of instruments of the system, and I have obtained a peculiarly eflicient device.

Having thus described my invention, what I claim is 1. In a telephone system the combination of a local transmitter comprising a battery and a transmitting-circuit, a main-line circuit, a receiver comprising a diaphragm, a core for operating the said diaphragm, an induction-coil surrounding the said core for magnetically affecting the said core and having two coils, one of said coils formed of coarse wire of few turns and connected in series with the said local circuit, the other of said coils formed of fine wire of many turns and connected in series with the said coil of coarse wire and the main line, as set forth.

2. In a telephone system the combination of a local transmitting-circuit comprising a battery and a transmitter, of main-line circuit, a receiving means comprising two magneto-telephones, one of said telephones having a diaphragm, a magnetic core for operating said diaphragm, an induction-coil surrounding the said core and for magnetically affecting the said core and having two coils, one of said coils being formed of coarse wire of few turns and in series with the said local transmitting circuit and in shunt of the main-line circuit, the other of said coils formed of fine wire of many turns and connected in series with the main line and the other telephone, as set forth.

3. In a telephone system the combination of a transmitting-circuit comprising a battery and a transmitter, a main-line circuit, a telephone-receiver havin a diaphragm, a core for operating the sai diaphragm, an induction-coil located on the said core having two coils, one of said coils constituting a transmitting-coil connected in series with the said transmitting-circuit, the other of said coils constituting a receiving-coil and connected in series with the said main-line circuit and in series with two parts of the said transmitting-circuit one of the said parts comprising the said transmitting-coil.

CHARLES G. BURKE.

Witnesses:

M. LAWSON DYER, BENJAMIN MILLER. 

